Gun trunnion



14, 1951 H. F. FRANKLIN 2,564,568

GUN TRUNNION 2 Sheets-Sheet 1 Filed Nov. 10, 1945 INVENTOR .b uberf fi fiemk/in HTTOE/VE Y H. F. FRANKLIN GUN TRUNNION Aug. 14, 1951 2 Sheets-Sheet 2 Filed Nov. 10, 1943 ATTORNEY Patented Aug. 14, .1951

GUN TRUNNION Hubert F. Franklin, Baldwin, N. Y., assignor to Republic Aviation Corporation, a corporation of Delaware Application November 10, 1943, Serial No. 509,717

6 Claims. 1

This invention relates to gun trunnions or mounts, of the universal type, and contemplates a device of this character having independent adjustments for the horizontal and the vertical planes, in which the gun, such as a machine gun may be quickly and readily mounted and from which it may be as quickly and as readily detached, all without affecting the adjustments of the trunnion or mount but permitting any necessary or desirable adjustments while the gun is supported by the trunnion.

With the above and other objects in view, as will be apparent, the invention consists in the construction, combination and arrangement of parts, all as hereinafter more fully described, claimed and illustrated in the accompanying drawings, wherein- Fig. 1 is a plan view of a gun mount or trunnion constructed in accordance with the present invention:

Fig. 2 is a transverse section along line 2-2 of Fig. 1 illustrating the mount in elevation and a part of its support in section:

Fig. 3 is a transverse section along line 33 of Fig. 1:

Fig. 4 is an end elevation of the trunnion or mount:

Fig. 5 is a vertical section along line 5-5 of Fig. 3: and I Fig. 6 is a fragmentary section similar to Fig. 3 illustrating a modified form of this invention.

As is well known, a machine gun, especially when mounted in the wing of an aircraft, has a double support, viz. an adjustable rear mount cooperating with its butt end assembly and a trunnion structure spaced from the rear gun mount forwardly of the gun barrel or jacket and cooperating with the barrel or jacket at some point between the butt end assembly and the muzzle of the gun. As the rear gun mount, which forms no part of the present invention, is usually adjustable in both the vertical (elevation) and the horizontal (azimuth) planes for aiming purposes, the trunnion structure; forming the subject of the present invention and cooperating with the rear mount for the support of the gun, is movable about axes lying in these planes with the aiming movements of the rear gun mount. At the same time the instant invention incorporates means for relatively small independent adjustments of the trunnion structure in both the vertical and the horizontal planes to permit of a true centering of'the gun and an accurate initial aiming adjustment in either or both of these planes, which adjustments once having been made become fixed or permanent. This trunnion or mount structure also provides for these several adjustments to be effected while .the gun is engaged within or by the trunnion Reference being had more particularly to the drawings, I0 designates a supporting structure such as the transverse ribs of an aircraft wing structure, upon which and to which the trunnion or mount forming the subject matter of the present invention secures a machine gun. In the drawings, I I designates the barrel of the gun, and I2 the jacket therefor. The jacket I2 of the gun is encircled and fixedly engaged by an adapter I3 having the conical journals I4 at the ends of its vertical diameter.

The gun mount or trunnion which is to receive and cooperate with an adapter I3 secured to a machine gun comprises a lower jaw I5 and an upper jaw I6. The lower jaw I5 is shaped to conform generally to the contour of the jacket I2 and the adapter I3 and is mounted between the ribs ID for pivotal movement about a horizontal axis to permit of the elevation-a1 aiming adjustment of the gun. That is accomplished by providing a supporting bearing H at each end of the lower jaw I5, each of which is pivotally and adjustably secured to one of the ribs II] as hereinafter more fully described. One of the supporting bearings H of the lower jaw I5 is provided on its upper side with a lug I8 to be received between a pair of ears I9 at the corresponding end of the upper jaw I6. The lug I8 and the ears I9 are pivotally secured together by a bolt 20.

In this manner the upper jaw It is hinged to,

the lower jaw I5 That end of the upper jaw I6 opposed to the hing comprisin the ears I9, lug I8 and bolt 20 is provided with a substantially horizontal projection 2I having a longitudinal groove 22 in the outer face thereof. This projection 2I extends over and lies substantially parallel to the inner end of the adjacent supporting bearing I1. To secure the free or unhinged end of the upper jaw I6 to the lower jaw I5, a yoke 23, provided with the arms 23', spans the jaws |5--I6 with its arms on opposed sides of the jaws and pivoted as at 24. at their terminals to the lower jaw below and in approximate alignment with the inner end of the adjacent supporting bearing I1. Medially of their length the arms 23' of the yoke are bent inwardly, as at 23", toward the approximate -Vertical center of the bearing, and this bend occurs at or near the horizontal projection 2| of the upper jaw IS.

A look operating rod 25 is threaded through the yoke 23 medially of its length between the arms 23' thereof and in order to provide a substantial mounting for this rod 25 a sleeve 26 is secured to the inner face of the yoke 23 in align: ment ith th pa a through which th r 25 is threaded. The interior of this sleeve 26 is threaded in continuation of the threads of the opening in the yoke through which the reel 2 passes and since the sleeve 26 in effect constitutes a unitary piece with theygke 23, having? threaded passage through these le ments fer co? operation with the threads of the rod 25, an elongated threaded bearing is provided for the rod 25, A shell 21 encircles the rod"25 and is provided with a series of locking depressions 28 in its outer end wall which cooperate with a wing nut 29 fixed to th od- A c mpressed co s in 39 is interposed between the engl wall' of the shell and yoke 23 to constantly force the shell upwardly 0 contact with the inner fidge of a wing nut 29" fixedly secured to the projecting end of the rod12 5, whereby the wing nut'is seated in one or the other of the depressions 2'8 and is held thereby from any tendency to rotate relatively to the shell or to the yoke. To prevent the shell 2'! from rotating with respect to the rod 25 and the yoke 23, it is provided with a pair of extensions 3|, one upon each side of the yoke 23, spaced one from theptherto provide a space for the reception of the yoke. 'These extensions 3| at all times contact with the edges of the yoke 23 regardless of the position of the shell 2! and prevent any rotary movement of the latter relative to either theyoke 23 or to therod 25. V

'To'bra'ce the sleeve 26, as well as the arms 23' of the yp ke23, a pair of plates 32 are interposed betw en il er 23- ad n to the r infla w t th s e be (if t e Y k 3 and the e plates 32 rest flush one against the other ex: Pt'whem th re e'ch'ben o war ly as a 3'3, vto embrace the s1eeve26. The plates32 may be welded or otherwise permanently secured to sf m m er f he 9K? 23 w t m 3' ihe fae to e c other and at their ce er where they" cooperate with the sleeve 26, sepa.

rate, as at 3 3, to combine in creating a passage iii 'whw ro gh wh c e sle e 'sxt nde and pass sht'its inner end the adjusting rod 25 is con; nected 'to'a pin 34 by means of a swiveled con. nection 35 As the rod 25 rotates it, of course, it Well th o h t ke Z d t e heme S e e 2|ifand is adjusted with respect to these elements.

By reason of the swivel or loose rotary connection 35 between the inner end of t is 1951 ansi' the pin 34, this Pin moves with therod along the axis of the rod but does not rotate with it; l Once the rod 25 has attained the desired adjusted position with respect to the yoke 23, the wing nut 29, by which the rod is rotated and adjusted, automatically becomes seated in the radiating re-1 cesses 28 in the outer wall of the shell 21 thereby ackin th r d rqm u the tah h,

Ju t above 1 dS 3" n t e a m 23' of he Y k 23 a d n a Pl ne p oxim tin t plane of the projection 2| of the upper jaw l6, each arm 23 is provided with a slot'36, the slot 35 ofohe arm being aligned transversely of the w t the s qtifi o e e qs e arm A l k 9 37 h ll p s 5 HE e ds 5 919 ea ingl m u ted betwee h w e q jthe 4 yoke by means of the ears 38 being slidably re ceived in the slots 36. Medially of this length this look bar is connected or fixed to the pin 34 so that as the pin is moved towards and away from projecting portion 2| of the movable jaw l6 under the influence of the wing nut 29, the lock bar 31 similarly moves. On its under surface and extending longitudinally of itslength, the lock bar has a r b 39.110. be d'in the ro v .2 in the horizontal projection 2| of the upper jaw l6 when the lock bar 31 has reached the lower end of its permissible path of movement. Since the jaws N5 and H are of relatively soft metal it is undesirable to co eentrate any great pressure at a single point. Therefore the bar 31 acts to distribute the clamping pressure between the jaw and prevents any concentration thereof.

*From the foregoing it is apparent that the lower or stationary jaw l5, once its ultimate adjustment in a horizontal plane has been attained, occupies a constant position with reference to the ribs it] by and between which it is supported in a manner to be hereinafter described. Since the yoke 23 is piyotedto one end of the lower or stationary jaw l5 and thefupper movable jaw I6 is pivotedto the opposite end'of the lower jaw, the jaws may be closed or opened by swinging the jaw Hi toa nd away from the jaw l5, and

when closed the yoke 23 may be positioned in Fig. '2 to lock the jaw it to the jaw |5 out: wardly with respect thereto, When the jaws are relatively positioned as shown in the drawings the projection 2| of the upper movable jaw I6, is over andlahove the corresponding portion of the ii ed'or-lower jaw l5, whereupon the yoke 23 may be swungtoa substantially vertical posi-. tion with the lock bar 31 above the projection 2|. The rotation of the wing nut 29 will then cause therpd :25 and pin 34 to move downwardly in the sleeve 26 to bring the lock bar 31 into contact with the projection 2| andlseat the rib 39 in the groove'22 thereof. The continued rotation of the rod in the same direction will cause a pressure t he smar .5 1 1991; the free end of the upper jaw I 6 and will lock it to the corresponding end of the lower jaw I5 It is to be observed that a space remains between the free end of the jaw i6 and the stationary jaw I5 when the jaws are in closed or looking position. As it is th fu ciich O the Prese t dev e o suppo a un or m v n in t o lanes. a d e this withoutlundue friction and any playpthe provision of this space permits of arange ofadjustment of pressure at all times to accomplish this end. The rib v3S of the lock bar 3'! SQ'hted in the groove 22 oi the projection 2| effectively o er omes an tendency vo t e o e to swi about its pivot and away frornlo'clzing engagew n -W h reiesiioh 2' c the uppe bfv: able jaw 16. Also the cooperation between the wingfnut 23 the radial depressions 23 in the end 'wall of the shell 21 will prevent any unintentional retrograde'movement of the wing nut l p J ct o 2| and permit the p r jaw to be shifted about its pivot 20.

Forcooperation with the conical journals I4 formed ormounted on the adapter I3 a pair of bearings 46 is provided, one bearing being centrally positioned in the upper jaw I6 and the other similarly situated in the lower fixed. jaw I5, said bearings being aligned vertically of the trunnion structure. Each of these bearings 40 is threaded into its cooperating jaw I5 or I6'and is held in its adjusted position by a nut 4! and a washer 42. The outer end of each bearing 46 is provided with one or more recesses 43 for the reception of a wrench by which the position of the bearing with reference to its jaw may be determined.

The inner end of each bearing 40 is provided with a conical seat 40 for the reception of the conical journals I4 formed on the adapter I3. This structure provides a mount for the gun movable about a vertical axis, and the adjustments provided for the bearings 40 permit of the adjustment of the gun and adapter in a vertical plane. The cooperation of the conical journals I4 with the conical seats 46' of the bearings 40 manifestly centers the gun in a horizontal plane with respectto the mount or trunnion structure as a whole. In short, the cooperation between the journals I4 and the bearings 49, together with the adjustment of the latter, not only centers the gun I2 carried by the adapter l3 with respect to the bearings but also permits 1 the gun to swing in a horizontal plane. By adjusting the bearings 40, the gun as a whole, together with its adapter I3, may be adjusted in a vertical plane between the jaws I5 and I6 of the mounting.

To support the mount between the ribs ID of the wing structure (not shown) a plate 44 is secured to each rib I6 and each plate carries a hollow horizontal journal 45 in the form of a truncated cone. These plates 44 may be mounted against either face of the supporting ribs III, one of them preferably being positioned against the face of its coacting rib l disposed away from the jaws II6 and to that end an aperture must be provided in the rib through which the journal 45 passes. the ribs ID by a series of bolts 46.

-As above pointed out, each end of the stationary or lower jaw I5 is provided with an outstanding cylindrical supporting bearing I1 aligned one with the other. These bearings project towards and receive the journals 45. In order to adjust the entire bearing in a horizontal plane between the journals 45, there is interposed between the supporting bearings I7 and the conical journals 45 an adjusting mechanism. This mechanism for each bearing I1 comprises an interiorly threaded bushing 41 inserted in each supporting bearing I! and coextensive therewith. This bushing has a tight friction fit or is otherwise fixedly secured within its bearing I I so that The plates 44 are secured to there is no relative movement between the supiary bearing is adjustable within and removable.

from the bushing 41 by a wrench engaging the inner end of the auxiliary bearing through the medium of the recesses 5| provided for that purpose. The inner end wall 45' of the journal 45 is provided with a splined aperture inwhich a splined boss 52 of the nut 53 is received. Abolt 54 having the head 55 passes through a washer 56, and wall 45' and projects into the journal 45 where it is engaged by the nut 53. As the washer 56 bears against the shoulder at the inner end of the conical seat 49 of the auxiliary bearing 48 and as the nut 53 cannot rotate by reason of its fixed splined connection with the inner end Wall 45 of the journal 45, and since the journal 45 is immovable, the rotation of the head 55 of the bolt forces the conical seat 49 of the auxiliary bearing 48 outwardly on the conical journal 45. In this manner the conical seat 49 of the auxiliary bearing 48 is adjusted to snugly engage the conical surface of the journal 45 and any looseness or play therebetween is eliminated.

.Furthermore, the engagement of the washer 56 with the shoulder at the inner end of the conical seat 49 of auxiliary bearing 48 preventsany axial movement between the journal 45 and the auxiliary bearing 48.

To move or adjust the mount in a horizontal plane, the bolts 54 are loosened, thus freeing the washers 56 from engagement with the auxiliary bearings 48. The auxiliary bearings 48 are then rotated the same amount and in the same direction in their respective threaded bushings 41 until the desired horizontal movement has been accomplished. To secure the mount in this position, the bolts 54 are retightened until the washers 56 reengage the shoulders on the inner end of the conical seats 49 of the auxiliary bearings 48 and the conical seats 49 of the auxiliary bearings 48 are snugly engaged with the conical surfaces of the journals 45.

It is to be understood that the adjustments required to properly center the gun with respect to the bearing, the ribs I0 and the leading edge of the wing structure through which it operates are relatively small, so that any large movement of the bearings 48 and/or of the auxiliary bearings 48 is unnecessary. However, by adjusting the bearings 40, threading one outwardly of its jaw, and threading the other inwardly of its jaw the entire gun and adapter I3 may be adjusted in a vertical plane with respect to the jaws. Once these adjustments have been attained so that the gun is initially sighted and properly centered, they become fixed and the upper hinged jaw I6.

may be released as above described and the gun removed therefrom, or the gun may be returned to its mounting and engaged between the jaws I5 and I6 without affecting these adjustments in the horizontal and vertical planes.

In Fig. 6 is illustrated a modification of the mechanism by which the free end of the hinged or upper jaw I6 is attached to one of the supported bearings II. The projection 2| at the end of the jaw I6 is, in this form of the invention, engaged by a ring 57 which has an internal flange 58. threaded for engagement with the external threads 59 on the exterior of the adjacent supporting bearing IT. The rotation of the locking ring 51 for travel inwardly causes the lip 60.

thereof to engage over the upper surface-ofthe jaw downwardly into clamping position, By re versing' thei'rotationofltheiringififiitheiiprojection ll iofithe supper-ior 'hinged jaw L6: is releasedi and the a aw. .isz'them free to :swingab-out .itsihinge 20. Inibothiforms of the invention-attic. free end: of the jaw lfiis provided with: a central opening. 6 l by 'the rojections $2, :the inner faces or which: incIineLupWardIyLandJ- inwardly. These innensurfiaces contact with the (upper portion oi the eadjoining supporting 3 bearing I I upon each 'side thereof, thereby creating -a. cam action L bemeerr the'f-ree end of: the jaw 6 :and the bearing 1 whereby aany. irregularities. in: the pivot :of the jaw L6,:which might otherwise throw the jaw out ofperiectialignment withthe bearings l1 and with :the lower fixed jam 5,: are :overcome and auperiectzalignment andcontact is obtained. Fro-m itheforegoingdt :isimanifest that the present trunnionustructure enables themgun to be adiusted by (the manipulation of the rear igun mount for aiming:purposes by providingfor' its oscillationlabout the vertical: axis represented by the :g'youmals [4 and coac'ting bearings 40 and about the horizontal axis represented by the bearings: li and-48. and the journals' fiE. Furthermoreitheadjustmentof thetrunnion-structure as a whole in the horizontal plane by adjusting the bearings "and Won the journals; andthetadiustment 'of the adapter in. the vertical plane by the-adjustment-of the bearings w relative to the jaws" i i-and 16,- makes possible an'initialpentering lot the r g-u-n withlll the trunnion structure which when once attained remains unchanged regardless .of the 'removal of the gun or of its returna-to the trunnion.

*Whatis claimedis:

.L 'lhe-combination with'a pair of conical trunnlons, of a primary jaw, opposed supporting bearings on said jaw for -the reception of said truni iionsgan auxiliary bearingad-justablymounted in each supporting bearing and-provided withsa cOnicaIsur-face for pivotal cooperation-with the engaged-trunnion, -'a connection between each trunnion --and"- its coacting auxiliary bearing to adjust'the position of the auxiliary bearing in its supporting bearing and with respect to the cooperating trunnion, a secondary jaw hinged to one end'of said primary jaw, fastening means carried by the primary jaw 'for releasably securing the free endof the secondary jaw thereto, opposed bearingscarried by the-secondary "and primary jaws'and adjustable with respect thereto, and-an aidapter to 'be positioned between said jaws and having --journals to -be' pivotally engaged in said adjustablebearings.

. 2. The combinationwith arr-annular adapter having diametrically *opposedjournals, of a primary jaw, opposedsupporting bearings at the endsofsaid jaw, fixed trunnions mounted to be received in said supporting bearings, auxiliary bearings interposed between said supporting bearingsand said trunnions, adjustable connections betweenflsaid' trunnions and said auxiliary bearingswhereby the position of the latter may be adjusted with respect to the former,- asecondary jaw hinged at one end to saidiprimarydaw,

an'engagmg member carried bysaid primary jaw torleasablyengago the other or free end of the secondary jaw, and opposed bearings, one attached to 'each of said jaws,'for the reception of the journals onsaid'adapter and adjustablerelative' to said jaws to position said adapter between said jaws.

"3."',Ihe combination with a generallyecircular gun adapter having diametrically-iopposed journa1s,'-of amount providing universal" movement 8 for :s'aid:. azia1i ter,:"said mount coniprising;a;pri mary; jaw and; a movablesecondary jaw arranged for:openingeandsclosing with respect to the-.primary jaw; said jawshaving their opposed faces disposedfin espacedeapart relation to providewa clearance intermediate their ends for. the adapter; bearingsadjustably carriediby said jaws tfori'rer ception of the.opposed.journals of the adapter,.

supporting bearingsiupon theends of the primary jaw,ifixed conical trunnions projecting within said supporting bearings, auxiliary conicalbearingsrzmounted'interinediatesaid supporting :bearings .and. trunnions, said auxiliary bearings being movable longitudinally of said supporting bearings, 'and :adjustable 1 connections for maintaining the :auxiliary bearings and trunnionsagainst relativc displacement.

The combination with'a. generallyecircular gun' za'dapter having rdiametricallyiopposed. jourr rials, :of -a =:mount providing universal move.- ment ior saidhadapter, said mount comprising a primary jaw ands-a secondary jaws arranged for opening. and closing movementwithrespect to theiprimary jawgsaid jaws having their iop posed racessdisposed in spaced-apart relation-to provide aaclearanceintermediate their ends-:for the adapter; bearingscarrie'd by said jaws forvthe reception-wit the :opposed journalssofi the adapter, supporting'nbearings. at the .ends of the. primary jaw,' fixedi trunnions: projecting within .said' .supporting bearings, an auxiliary bearing interposed :between each trunnion and supporting bearing; and means: for adjusting each auxiliary bearing :withinitss associated supporting .bearing to position the primary jaw relative tosaidztrunnions.

'-5." 'I-he acombination with .an annular .igun adapter :having diametrically-opposed journals, of -a primary jaw, opposed supporting bearings at' the ends of said jaw, fixed. trunnions mounted to be \receive'din said supporting bearings, auxiliary bearings between said supporting bearings 1 and said trunnions, threaded .means between said supporting bearings and saideauxiliary bearingswhereby the positions of the anxi-liary -bearings may be independently adjusted longitudinally within the supporting bearingspa secondary-yaw hinged-at one end: of said primary --jaw-andndisposed inspaced relation intermediate 1135' length to: the primary iawxtosprovide clearance for the adapter, an engaging member-carried by'said primaryjaw to releasably-engage" the other-end of the'secondary jaw, 0pposed-adapted bearings, one attached to each of said jaws,-;f-or the reception of the journals on said adapter, and means 'for adjusting said adapter 'bearings relativeto said jaws to positionsaid adapter between said jaws.

6. The combination with an annular gun adapter having diametrically-opposed journais, of a primaryf'jaw, opposed supporting bearings at theends of said jaw, fixed trunnions mountedto be received insaid supporting bearings, auxiliary bearings betweensaid supporting bearings and said trunnions, threaded means between said supporting bearings and said auxiliary bearings'whereby" the positions ofthe aux iliary bearings may be adjusted longitudinally within the supporting bearings, a washer within each auxiliarybearingiand engaging a stop on saidiaiuxiliary bearing and a tie member extend-' ing between the adjacent trunnion and the washerfor; adjustably positioning the washer in engagement with the stop to prevent retrograde movement" of'the auxiliary bearing, a secondary jaw hinged at one end to said primary jaw and disposed in spaced relation intermediate its length to the primary jaw to provide clearance for the adapter, an engaging member carried by said primary jaw to releasably engage the other end of the secondary jaw, opposed adapter bearings, one attached to each of said jaws, for the reception of the journals on said adapter, and means for adjusting said adapter bearings relative to said jaws to position said adapter be- 10 tween said jaws for pivotal movement.

HUBERT F. FRANKLIN.

REFERENCES CITED The following references are of record in the 15 file of this patent:

Number Number 10 UNITED STATES PATENTS Name Date Stone Sept. 17, 1867 Nilsson Q Feb. 19, 1895 McLeod June 1, 1897 Sovereign Dec. 6, 1898 Jackson Aug. 15, 1899 Frissell Feb. 10, 1914 North May 27, 1919 Norman May 11, 1920 FOREIGN PATENTS Country Date Italy Apr. 14, 1936 France Feb. 7, 1938 Switzerland May 16, 1941 

